Modulevalidation-1.3.3Haskell2010

Data.Validation.Validation

A data type similar to Data.Either that accumulates failures.

1 type
4 classes
5 values

Packagevalidation-1.3.3
Exports10
LanguageHaskell2010
LicenceBSD-3-Clause
SourceValidation.hs

Data type

1 declaration

datadata Validation err a

A Validation is either a value of the type err or a, similar to Either. However, the Applicative instance for Validation accumulates errors using a Semigroup on err. In contrast, the Applicative for Either returns only the first error.

A consequence of this is that Validation has no Bind or Monad instance. This is because such an instance would violate the law that a Monad's ap must equal the Applicative's <*>

See the README for usage examples.

Constructors

Failure err
Success a

Instances45Bifoldable, Bifoldable1, Bifunctor, Bitraversable, Eq2, Ord2, …

Bifoldable ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Data.Bifoldable(Bifoldable(bifoldr))>>> bifoldr (\e r -> show e ++ r) (\a r -> show a ++ r) "" (Failure 1 :: Validation Int Int)"1"

Example1 expression

>>> bifoldr (\e r -> show e ++ r) (\a r -> show a ++ r) "" (Success 2 :: Validation Int Int)"2"

Bifoldable1 ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Bifunctor ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Data.Bifunctor(Bifunctor(bimap))>>> bimap show (+1) (Failure 1 :: Validation Int Int)Failure "1"

Example1 expression

>>> bimap show (+1) (Success 1 :: Validation Int Int)Success 2

Bitraversable ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Data.Bitraversable(Bitraversable(bitraverse))>>> bitraverse (\e -> [e, e+1]) (\a -> [a, a*2]) (Failure 1 :: Validation Int Int)[Failure 1,Failure 2]

Example1 expression

>>> bitraverse (\e -> [e, e+1]) (\a -> [a, a*2]) (Success 3 :: Validation Int Int)[Success 3,Success 6]

Eq2 ValidationDefined in validation-1.3.3 · Data.Validation.Validation
Ord2 ValidationDefined in validation-1.3.3 · Data.Validation.Validation
Show2 ValidationDefined in validation-1.3.3 · Data.Validation.Validation
Assoc ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Swap ValidationDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Data.Bifunctor.Swap(Swap(swap))>>> swap (Failure "err" :: Validation String Int)Success "err"

Example1 expression

>>> swap (Success 1 :: Validation String Int)Failure 1

Bitraversable1 ValidationDefined in validation-1.3.3 · Data.Validation.Validation
Generic1 (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Functor (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Example1 expression

>>> fmap (+1) (Success 2 :: Validation String Int)Success 3

Example1 expression

>>> fmap (+1) (Failure "err" :: Validation String Int)Failure "err"

Semigroup err => Applicative (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Delegates to the Apply instance, accumulating errors with <>.
Example1 expression
```
>>> pure (+1) <*> pure 2 :: Validation [String] IntSuccess 3
```
Example1 expression
```
>>> Failure ["e1"] <*> Failure ["e2"] :: Validation [String] IntFailure ["e1","e2"]
```
Foldable (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Example1 expression
```
>>> foldr (:) [] (Success 1 :: Validation String Int)[1]
```
Example1 expression
```
>>> foldr (:) [] (Failure "err" :: Validation String Int)[]
```

Traversable (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Example1 expression

>>> traverse (\x -> [x, x+1]) (Success 1 :: Validation String Int)[Success 1,Success 2]

Example1 expression

>>> traverse (\x -> [x, x+1]) (Failure "err" :: Validation String Int)[Failure "err"]

Monoid err => Alternative (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Eq err => Eq1 (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Ord err => Ord1 (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Show err => Show1 (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Semigroup err => Alt (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Tries the left, then the right, accumulating errors on two failures.

Example2 expressions

>>> import Data.Functor.Alt(Alt((<!>)))>>> Success 1 <!> Success 2 :: Validation [String] IntSuccess 1

Example1 expression

>>> Failure ["e1"] <!> Success 2 :: Validation [String] IntSuccess 2

Example1 expression

>>> Success 1 <!> Failure ["e2"] :: Validation [String] IntSuccess 1

Example1 expression

>>> Failure ["e1"] <!> Failure ["e2"] :: Validation [String] IntFailure ["e1","e2"]

Semigroup err => Apply (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Accumulates errors on the left using Semigroup.

Example2 expressions

>>> import Data.Functor.Apply(Apply((<.>)))>>> Success (+1) <.> Success 2 :: Validation [String] IntSuccess 3

Example1 expression

>>> Failure ["e1"] <.> Success 2 :: Validation [String] IntFailure ["e1"]

Example1 expression

>>> Success (+1) <.> Failure ["e2"] :: Validation [String] IntFailure ["e2"]

Example1 expression

>>> Failure ["e1"] <.> Failure ["e2"] :: Validation [String] IntFailure ["e1","e2"]

Extend (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation
Monoid err => Plus (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Semigroup err => Selective (Validation err)Defined in validation-1.3.3 · Data.Validation.Validation

Skips the second effect on Failure.

Example2 expressions

>>> import Control.Selective(Selective(select))>>> select (Success (Right 1)) (Success (+1)) :: Validation [String] IntSuccess 1

Example1 expression

>>> select (Success (Left 1)) (Success (+1)) :: Validation [String] IntSuccess 2

Example1 expression

>>> select (Failure ["e1"]) (Success (+1)) :: Validation [String] IntFailure ["e1"]

Example1 expression

>>> select (Failure ["e1"]) (Failure ["e2"]) :: Validation [String] IntFailure ["e1"]

Sieve (ValidatorProfunctor err) (Validation err)Defined in validation-1.3.3 · Data.Validation.Validator
Example1 expression
```
>>> sieve vpFromInput 3Success 4
```
Example1 expression
```
>>> sieve (vpErr ["e"]) 0Failure ["e"]
```
(Eq err, Eq a) => Eq (Validation err a)Defined in validation-1.3.3 · Data.Validation.Validation
(Data err, Data a) => Data (Validation err a)Defined in validation-1.3.3 · Data.Validation.Validation
(Ord err, Ord a) => Ord (Validation err a)Defined in validation-1.3.3 · Data.Validation.Validation
(Show err, Show a) => Show (Validation err a)Defined in validation-1.3.3 · Data.Validation.Validation
Generic (Validation err a)Defined in validation-1.3.3 · Data.Validation.Validation

Semigroup e => Semigroup (Validation e a)Defined in validation-1.3.3 · Data.Validation.Validation

First Success wins; two Failures are combined with <>.

Example1 expression

>>> Failure ["e1"] <> Failure ["e2"] :: Validation [String] IntFailure ["e1","e2"]

Example1 expression

>>> Failure ["e1"] <> Success 2 :: Validation [String] IntSuccess 2

Example1 expression

>>> Success 1 <> Failure ["e2"] :: Validation [String] IntSuccess 1

Example1 expression

>>> Success 1 <> Success 2 :: Validation [String] IntSuccess 1

Monoid e => Monoid (Validation e a)Defined in validation-1.3.3 · Data.Validation.Validation
Example1 expression
```
>>> mempty :: Validation [String] IntFailure []
```
(NFData e, NFData a) => NFData (Validation e a)Defined in validation-1.3.3 · Data.Validation.Validation
Example2 expressions
```
>>> import Control.DeepSeq(rnf)>>> rnf (Success 1 :: Validation String Int)()
```
Example1 expression
```
>>> rnf (Failure "err" :: Validation String Int)()
```
AsValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation
GetValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation
HasValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation
ReviewValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

AsValidationMonadT (Validation err a) err Identity aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens((^?))>>> (Success 1 :: Validation String Int) ^? _ValidationMonadTJust (ValidationMonadT (Identity (Success 1)))

GetValidationMonadT (Validation err a) err Identity aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(view)>>> view getValidationMonadT (Success 1 :: Validation String Int)ValidationMonadT (Identity (Success 1))

HasValidationMonadT (Validation err a) err Identity aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(view)>>> view validationMonadT (Success 1 :: Validation String Int)ValidationMonadT (Identity (Success 1))

ReviewValidationMonadT (Validation err a) err Identity aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(review)>>> review reviewValidationMonadT (ValidationMonadT (Identity (Success 1))) :: Validation String IntSuccess 1

Injection1 (Validation a b) (Validation a' b) a a'Defined in validation-1.3.3 · Data.Validation.Validation

The first constructor, Failure. The same as __Failure.

Example2 expressions

>>> import Control.Lens((^?), (#), over)>>> (Failure "err" :: Validation String Int) ^? _I1Just "err"

Example1 expression

>>> (Success 1 :: Validation String Int) ^? _I1Nothing

Example1 expression

>>> _I1 # "err" :: Validation String IntFailure "err"

Example1 expression

>>> over _I1 length (Failure "err" :: Validation String Int)Failure 3

Injection2 (Validation a b) (Validation a b') b b'Defined in validation-1.3.3 · Data.Validation.Validation

The second constructor, Success. The same as __Success.

Example2 expressions

>>> import Control.Lens((^?), (#), over)>>> (Success 1 :: Validation String Int) ^? _I2Just 1

Example1 expression

>>> (Failure "err" :: Validation String Int) ^? _I2Nothing

Example1 expression

>>> _I2 # 1 :: Validation String IntSuccess 1

Example1 expression

>>> over _I2 show (Success 1 :: Validation String Int)Success "1"

type Rep (Validation err a) = D1 ('MetaData "Validation" "Data.Validation.Validation" "validation-1.3.3-1rmGLJZm63vLrWVTj4XPXA" 'False) (C1 ('MetaCons "Failure" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 err)) :+: C1 ('MetaCons "Success" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))Defined in validation-1.3.3 · Data.Validation.Validation
type Rep1 (Validation err) = D1 ('MetaData "Validation" "Data.Validation.Validation" "validation-1.3.3-1rmGLJZm63vLrWVTj4XPXA" 'False) (C1 ('MetaCons "Failure" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 err)) :+: C1 ('MetaCons "Success" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))Defined in validation-1.3.3 · Data.Validation.Validation

Catamorphism

1 declaration

valuefoldValidation :: (a -> x) -> (b -> x) -> Validation a b -> x

Catamorphism for Validation.

Example1 expression

>>> foldValidation show show (Failure 1 :: Validation Int Int)"1"

Example1 expression

>>> foldValidation show show (Success 2 :: Validation Int Int)"2"

Optics

0 declarations

Classy lenses

classclass GetValidation s err a | s -> err a where

Class for types that have a Getter to a Validation.

Methods

getValidation :: Getter s (Validation err a)

Instances3GetValidation

GetValidation (Either err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Control.Lens(view)>>> view getValidation (Left "err" :: Either String Int)Failure "err"

Example1 expression

>>> view getValidation (Right 1 :: Either String Int)Success 1

GetValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

GetValidation (ValidationMonad err a) err aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(view)>>> view getValidation (ValidationMonadT (Identity (Success 1)) :: ValidationMonadT String Identity Int)Success 1

classclass GetValidation s err a => HasValidation s err a | s -> err a where

Class for types that have a Lens' to a Validation (as generated by makeClassy).

Methods

validation :: Lens' s (Validation err a)

Instances3HasValidation

HasValidation (Either err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Control.Lens(view, set)>>> view validation (Left "err" :: Either String Int)Failure "err"

Example1 expression

>>> set validation (Success 2 :: Validation String Int) (Left "err" :: Either String Int)Right 2

HasValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

HasValidation (ValidationMonad err a) err aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(view)>>> view validation (ValidationMonadT (Identity (Success 1)) :: ValidationMonadT String Identity Int)Success 1

Classy prisms

classclass ReviewValidation s err a | s -> err a where

Class for types that have a Review to a Validation.

Methods

reviewValidation :: Review s (Validation err a)
reviewFailure :: Review s err
reviewSuccess :: Review s a

Instances3ReviewValidation

ReviewValidation (Either err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Control.Lens((#))>>> reviewValidation # (Failure "err" :: Validation String Int) :: Either String IntLeft "err"

Example1 expression

>>> reviewValidation # (Success 1 :: Validation String Int) :: Either String IntRight 1

ReviewValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

Applicative m => ReviewValidation (ValidationMonadT err m a) err aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens(review)>>> review reviewValidation (Success 1 :: Validation String Int) :: ValidationMonadT String [] IntValidationMonadT [Success 1]

classclass ReviewValidation s err a => AsValidation s err a | s -> err a where

Class for types that have a Prism' to a Validation (as generated by makeClassyPrisms).

Methods

_Validation :: Prism' s (Validation err a)
_Failure :: Prism' s err
_Success :: Prism' s a

Instances3AsValidation

AsValidation (Either err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

Example2 expressions

>>> import Control.Lens((^?), (#))>>> _Validation # (Failure "err" :: Validation String Int) :: Either String IntLeft "err"

Example1 expression

>>> (Left "err" :: Either String Int) ^? _ValidationJust (Failure "err")

Example1 expression

>>> (Right 1 :: Either String Int) ^? _ValidationJust (Success 1)

AsValidation (Validation err a) err aDefined in validation-1.3.3 · Data.Validation.Validation

AsValidation (ValidationMonad err a) err aDefined in validation-1.3.3 · Data.Validation.ValidationMonad

Example2 expressions

>>> import Control.Lens((^?))>>> (ValidationMonadT (Identity (Success 1)) :: ValidationMonadT String Identity Int) ^? _ValidationJust (Success 1)

Prisms

value__Failure

:: (Choice p, Applicative f)
=> p a (f a')
-> p (Validation a b) (f (Validation a' b))

Polymorphic Prism targeting the Failure constructor.

Example2 expressions

>>> import Control.Lens((^?), review)>>> review __Failure "err" :: Validation String IntFailure "err"

Example1 expression

>>> (Failure "err" :: Validation String Int) ^? __FailureJust "err"

Example1 expression

>>> (Success 1 :: Validation String Int) ^? __FailureNothing

value__Success

:: (Choice p, Applicative f)
=> p b (f b')
-> p (Validation a b) (f (Validation a b'))

Polymorphic Prism targeting the Success constructor.

Example2 expressions

>>> import Control.Lens((^?), review)>>> review __Success 1 :: Validation String IntSuccess 1

Example1 expression

>>> (Success 1 :: Validation String Int) ^? __SuccessJust 1

Example1 expression

>>> (Failure "err" :: Validation String Int) ^? __SuccessNothing

Isomorphisms

valueeither

:: (Profunctor p, Functor f)
=> p (Either a b) (f (Either a' b'))
-> p (Validation a b) (f (Validation a' b'))

Isomorphism between Validation and Either.

Example2 expressions

>>> import Control.Lens(view)>>> view either (Failure "err" :: Validation String Int)Left "err"

Example1 expression

>>> view either (Success 1 :: Validation String Int)Right 1

valuecodiagonal

:: (Profunctor p, Functor f)
=> p (Bool, a) (f (Bool, a'))
-> p (Validation a a) (f (Validation a' a'))

Isomorphism between Validation a a and (Bool, a), where False corresponds to Failure.

Example2 expressions

>>> import Control.Lens(view)>>> view codiagonal (Failure "x" :: Validation String String)(False,"x")

Example1 expression

>>> view codiagonal (Success "x" :: Validation String String)(True,"x")